Foundation Batch For Class 7

REPRODUCTION IN PLANTS

HOW PLANTS CREATE NEW LIFE!

Introduction

Reproduction is the process by which plants produce new individuals of the same kind, ensuring the survival of their species. Plants reproduce in two main ways: asexual reproduction and sexual reproduction.

1. Asexual Reproduction

In asexual reproduction, new plants are produced from a single parent without seeds.

Types of Asexual Reproduction

a. Vegetative Propagation

  • New plants grow from parts like roots, stems, and leaves.
  • Examples:
    • Roots: Sweet potato.
    • Stems: Potato, sugarcane.
    • Leaves: Bryophyllum (buds form on leaf edges).

b. Budding

  • A small bulb-like structure (bud) forms on the parent plant, grows, and detaches.
  • Example: Yeast.

c. Fragmentation

  • The parent plant breaks into fragments, and each fragment grows into a new plant.
  • Example: Spirogyra (a type of algae).

d. Spore Formation

  • Plants produce tiny spores, which germinate into new plants under favorable conditions.
  • Example: Ferns, mosses.

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2. Sexual Reproduction

In sexual reproduction, new plants are formed through the fusion of male and female gametes (sex cells).

Parts of a Flower (Reproductive Organ)

A flower is the reproductive part of a plant.

  1. Male Part: Stamen
    • Anther: Produces pollen (male gametes).
    • Filament: Supports the anther.
  2. Female Part: Carpel (Pistil)
    • Stigma: Receives pollen.
    • Style: Connects stigma to ovary.
    • Ovary: Contains ovules (female gametes).
  3. Other Parts:
    • Petals: Attract pollinators.
    • Sepals: Protect the flower bud.

Pollination

Pollination is the transfer of pollen grains from the anther to the stigma.

Types of Pollination

  1. Self-Pollination:
    • Pollen transfers within the same flower or between flowers of the same plant.
  2. Cross-Pollination:
    • Pollen transfers from one plant to another.
    • Carried by wind, water, insects, or animals.

Fertilization

  • After pollination, the pollen grain travels to the ovule inside the ovary.
  • The male gamete fuses with the female gamete to form a zygote, which develops into a seed.

3. Seed Dispersal

Seeds need to be dispersed to grow into new plants. This avoids overcrowding and helps plants colonize new areas.

Methods of Seed Dispersal

  1. By Wind:
    • Seeds are light and have structures like wings or hairs.
    • Example: Cotton, maple.
  2. By Water:
    • Seeds float on water.
    • Example: Coconut, water lily.
  3. By Animals:
    • Animals eat fruits and disperse seeds through droppings or by carrying them on their fur.
    • Example: Guava, mango.
  4. By Explosion:
    • Some fruits burst open, scattering seeds.
    • Example: Pea, balsam.

Importance of Reproduction in Plants

  1. Ensures the survival of plant species.
  2. Maintains biodiversity.
  3. Provides food, oxygen, and raw materials for humans and animals.

Examples for Better Understanding

  1. Self-Pollination: Hibiscus, pea.
  2. Cross-Pollination: Apple, sunflower.
  3. Vegetative Propagation: Growing rose plants from cuttings.

Fun Activity

Pollination Experiment

  1. Take a cotton swab to mimic the role of a bee.
  2. Collect “pollen” from the anther of a flower.
  3. Transfer it to the stigma of another flower.
  4. Observe the pollen grains under a magnifying glass.

Practice Questions

  1. What is the difference between self-pollination and cross-pollination?
  2. Name the male and female reproductive parts of a flower.
  3. How does seed dispersal by animals help plants?
  4. Give two examples of plants that reproduce through vegetative propagation.

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Summary

Reproduction in plants is a fascinating process, ensuring that life continues on Earth. Asexual reproduction is simple and quick, while sexual reproduction involves the intricate process of pollination and fertilization. Seed dispersal helps plants spread and thrive in diverse environments.

With these processes, plants not only sustain their species but also support all life on Earth!

πŸ“ Multiple Choice Questions

1. Reproduction in plants ensures:
A) Death
B) Survival of species
C) Drying of plants
D) Decay

2. Asexual reproduction involves:
A) Two parents
B) One parent
C) Seeds only
D) Flowers only

3. Sexual reproduction involves:
A) One parent
B) No gametes
C) Fusion of gametes
D) Only roots

4. Vegetative propagation occurs through:
A) Seeds
B) Roots, stems, leaves
C) Flowers
D) Fruits

5. Potato reproduces by:
A) Leaves
B) Roots
C) Stem
D) Seeds

6. Bryophyllum reproduces through:
A) Roots
B) Leaves
C) Stem
D) Flowers

7. Yeast reproduces by:
A) Fragmentation
B) Budding
C) Spore formation
D) Seeds

8. Spirogyra reproduces by:
A) Budding
B) Fragmentation
C) Seeds
D) Roots

9. Ferns reproduce by:
A) Seeds
B) Budding
C) Spores
D) Roots

10. A flower is the:
A) Root
B) Stem
C) Reproductive part
D) Leaf

11. Male part of flower is:
A) Carpel
B) Stamen
C) Ovary
D) Stigma

12. Female part of flower is:
A) Stamen
B) Carpel
C) Anther
D) Filament

13. Anther produces:
A) Seeds
B) Ovules
C) Pollen
D) Fruit

14. Stigma receives:
A) Water
B) Pollen
C) Seeds
D) Roots

15. Ovary contains:
A) Seeds
B) Ovules
C) Leaves
D) Petals

16. Pollination is transfer of:
A) Seeds
B) Water
C) Pollen
D) Roots

17. Self-pollination occurs in:
A) Same plant
B) Different plant
C) Only insects
D) Only wind

18. Cross-pollination occurs between:
A) Same flower
B) Same plant
C) Different plants
D) Roots

19. Fertilization is:
A) Seed formation
B) Fusion of gametes
C) Pollination
D) Germination

20. Zygote develops into:
A) Root
B) Leaf
C) Seed
D) Stem

21. Petals help in:
A) Absorption
B) Attraction of pollinators
C) Digestion
D) Respiration

22. Sepals protect:
A) Roots
B) Stem
C) Bud
D) Seeds

23. Seeds are dispersed by:
A) Wind
B) Water
C) Animals
D) All of these

24. Coconut is dispersed by:
A) Wind
B) Water
C) Animals
D) Explosion

25. Cotton seeds are dispersed by:
A) Water
B) Wind
C) Animals
D) Explosion

26. Mango seeds are dispersed by:
A) Wind
B) Water
C) Animals
D) Explosion

27. Pea seeds are dispersed by:
A) Explosion
B) Water
C) Wind
D) Animals

28. Seed dispersal prevents:
A) Growth
B) Overcrowding
C) Reproduction
D) Germination

29. Which is asexual reproduction?
A) Pollination
B) Fertilization
C) Vegetative propagation
D) Seed formation

30. Which is sexual reproduction?
A) Budding
B) Fragmentation
C) Pollination and fertilization
D) Spore formation

31. Sugarcane reproduces by:
A) Leaves
B) Stem
C) Root
D) Seeds

32. Sweet potato reproduces by:
A) Stem
B) Root
C) Leaf
D) Flower

33. Budding involves:
A) Seeds
B) Bud formation
C) Roots
D) Leaves

34. Spores are:
A) Large structures
B) Tiny reproductive units
C) Roots
D) Leaves

35. Which needs pollination?
A) Asexual reproduction
B) Sexual reproduction
C) Fragmentation
D) Budding

36. Wind pollination requires:
A) Heavy seeds
B) Light pollen
C) Water
D) Animals

37. Fertilization occurs in:
A) Stigma
B) Style
C) Ovary
D) Petal

38. After fertilization, ovary becomes:
A) Root
B) Fruit
C) Stem
D) Leaf

39. Ovule develops into:
A) Fruit
B) Seed
C) Root
D) Stem

40. Example of self-pollination:
A) Sunflower
B) Apple
C) Pea
D) Mango

41. Example of cross-pollination:
A) Pea
B) Hibiscus
C) Apple
D) Potato

42. Pollination agents include:
A) Wind
B) Water
C) Insects
D) All of these

43. Vegetative propagation is:
A) Slow
B) Fast
C) Impossible
D) Harmful

44. Which plant reproduces by leaf buds?
A) Potato
B) Bryophyllum
C) Mango
D) Pea

45. Fragmentation occurs in:
A) Yeast
B) Spirogyra
C) Fern
D) Rose

46. A seed contains:
A) Embryo
B) Water
C) Leaves
D) Stem

47. Germination requires:
A) Oxygen
B) Water
C) Temperature
D) All of these

48. Which is NOT a method of asexual reproduction?
A) Budding
B) Fragmentation
C) Pollination
D) Spore formation

49. Which part connects stigma and ovary?
A) Filament
B) Style
C) Petal
D) Sepal

50. Reproduction helps in:
A) Extinction
B) Survival
C) Drying
D) Decay


βœ… Answer Key (At the End)

1-B, 2-B, 3-C, 4-B, 5-C, 6-B, 7-B, 8-B, 9-C, 10-C
11-B, 12-B, 13-C, 14-B, 15-B, 16-C, 17-A, 18-C, 19-B, 20-C
21-B, 22-C, 23-D, 24-B, 25-B, 26-C, 27-A, 28-B, 29-C, 30-C
31-B, 32-B, 33-B, 34-B, 35-B, 36-B, 37-C, 38-B, 39-B, 40-C
41-C, 42-D, 43-B, 44-B, 45-B, 46-A, 47-D, 48-C, 49-B, 50-B